Materials Data on La3TaO7 by Materials Project
La3TaO7 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.45 Å) and four longer (2.79 Å) La–O bond lengths. In the second La3+ site, La3+ is bonded to seven O2- atoms to form distorted LaO7 pentagonal bipyramids that share corners with two equivalent TaO6 octahedra, corners with three equivalent LaO7 pentagonal bipyramids, edges with two equivalent TaO6 octahedra, and edges with two equivalent LaO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are a spread of La–O bond distances ranging from 2.35–2.78 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with four equivalent LaO7 pentagonal bipyramids, and edges with four equivalent LaO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 27°. All Ta–O bond lengths are 2.01 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three La3+ and one Ta5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent La3+ and two equivalent Ta5+ atoms.